


In Which Killer Talks Too Much And Cross Is A Baby

by valeriavionics



Series: Nightmare's Gang in a Nutshell [1]
Category: Undertale (Video Game)
Genre: Bullying, Canon-Typical Violence, Cross can fight, Disassociation, Everyone else is as unhelpful as per usual, Killer likes it, M/M, Mentions of Xtale, Power Imbalance, Subspace, Subspace Abuse, Unresolved Sexual Tension, Wall Pinning
Language: English
Status: Completed
Published: 2020-11-18
Updated: 2020-11-18
Packaged: 2021-03-10 04:34:10
Rating: Mature
Warnings: Graphic Depictions Of Violence
Chapters: 1
Words: 3,048
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/27617705
Author URL: https://archiveofourown.org/users/valeriavionics/pseuds/valeriavionics
Summary: This was supposed to be a Kross spanking shot but as soon as I got to the actual spanking part, I got burnout, smh.
Relationships: Cross Sans/Killer Sans, Cross/Killer, Kross - Relationship
Series: Nightmare's Gang in a Nutshell [1]
Series URL: https://archiveofourown.org/series/2111619
Comments: 4
Kudos: 96





	In Which Killer Talks Too Much And Cross Is A Baby

Being recruited as one of Nightmare’s subordinates wasn’t how Cross planned things to go- In fact, many of the things that happened after Cross abandoned his AU were left at the mercy of his recklessness. He only had a few puzzle pieces of what he should do to fix his mistakes, but the whole picture didn’t become clear until the entity of negativity came into play as another piece.

He doesn’t know what Nightmare saw in him that he found valuable, what made him accept the soldier into his home and be confident in his abilities. Maybe he was putting Nightmare on a pedestal, but he can’t deny that the kind of approval he receives after a mission is successful is something he had been craving for years. If he’s sure of anything, it’s that he is useful for Nightmare more than just a medium to entertain or reach perfection.

Well, that wasn’t entirely true. Nightmare always demanded perfection, _precision_ , but Cross _wants_ to be precise, he _wants_ to do a good job because doing a good job means he’d get what he wanted as well.

It was mutually benefitting, with Nightmare having the most gain.

Unfortunately, this meant Cross had to learn how to do everything Nightmare’s way, included learning to work with his already pre-existing team.

The Royal Guard had already taught him the value of teamwork, and he was fine with it when it implied that having more people to back him up meant he could do a better job at protecting the Royal Family (at protecting _Frisk_ ). After the collapse of his world, he only had Chara to work with, and he wasn’t exactly the most cooperative partner to be stuck with- considering how taunting, derisive, and often manipulative he turned out to be.

But now, he almost misses those times. _Almost_ , because ever since Nightmare silenced Chara inside his head he’s been blissfully left alone with his thoughts… but at least the kid treated him like an adult that could manage harsh words and not like a babybones in need of coddling.

Like the skeletons Nightmare had gathered long before him.

“Hey Crossy, come sit with us, we were just talking about you!”, Killer calls him with that stupid grin he has when he’s about to start shit, and Cross can’t hide his displeasure at hearing his voice. Dust and Horror are there as well, staring at him with looks no better than Killer’s.

He makes a point of blatant dismissal by sitting on the opposite side on the table, hood pulled up and mouth tucked into his turtleneck.

“D’aw”, the other tsks, but there’s irritating mirth behind the whine, “You’re no fun.”

“Think baby woke up all grumpy”, Dust chimes in, dully, and Horror snickers, a hissed laugh that makes Cross’s socket twitch.

He’s found the best way to get this over with is to ignore them until the morning meeting was over, or at least, arrive just seconds before Nightmare did and avoid interaction altogether. The dark skeleton was punctual and it wasn’t hard to postpone the reunions, but Cross was _told_ he _had_ to be there at least ten minutes before they started.

Keeping his sight on the table, the monochromatic of the bunch crosses his arms, keeping his stoic façade to neglect the others from the satisfaction of seeing him frustrated.

“G’morning”, he replies gruffly, gaining nothing but louder laughter from Horror and Dust and a mocking head tilt from Killer. 

He doesn’t mind the humorless quips from Horror and Dust, their empty insults and jokes were just reflections of themselves, trying to somehow relate to him, to their timelines. Cross is not easily impressed by them- considering the many obvious differences between their worlds (he hates the fact that even if he looks okay, they still hold luck over his head by not knowing who their Creators are). Those two were _linear_ , two different possibilities from the “original” universe while Cross’ world was anything but, so they would _never_ have anything in common. 

No, Killer was forever the cause of his annoyance. He managed to be both a possibility and a completely different being than the rest- a fusion between a monster and a human, a mix Cross would never and doesn’t _want_ to become.

Every joke and expression felt like a provocation to Cross, less to welcome him to the gang and more to test him, to probe at his limits. Killer wasn’t covered in the same sludge as Nightmare, but his smile was equally as cutting, tearing through bone, through his shields, making Cross feel exposed, examined, ripped open like a stuffed doll for the world to see.

…Cross has always been a victim of his own dramatics, but in all seriousness, Killer had means to get on his nerves in ways even Chara couldn’t rival.

The doors leading to the opposite hall opened before they could retort, Nightmare carrying his usual ‘in charge’ posture along with a wave of dark mass that compressed at Cross’s soul almost immediately. Thankfully, it’s not influencing enough to give him anything near a breakdown, just so he knew the boss was there.

“I’ll make this brief, the four of you are to make yourselves useful and sparse for the next two days.”, going straight to the point, the soldier can tell Nightmare is not in the mood for interruptions. “Horror and Dust, you’re in charge of this week’s supplies raid, so be sensible and don’t drive attention to yourselves”.

That’s bad- not the pairing of Horror and Dust, they worked very well together. Horror was physically the strongest of the group, and Dust was cold, calculating; the perfect combination of brute force and brains.

No, it’s bad because that means Cross wouldn’t be paired with Dust this time, but with-

“Killer, you and Cross are in charge of Dancefell. Make sure the human doesn’t ruin their Genocide for a long time.”

Cross has to shove half of his face into his turtleneck to hide his obvious scorn, a fruitless disguise as Nightmare’s scowl lifts to a less irritated look. Meanwhile, Killer leans forward on the table, resting his chin on his hands in faux sweetness that makes Cross want to throw him off the fifth floor.

“Babysitting duty, huh?”, he pretty much purrs, sockets lidded and teeth on display, “Don’t worry, Crossy, I’ll protect you from the big bad dancing ballerinas.”

The second those words leave his wretched mouth, Cross bolts up to his feet, arm yanking itself away from his body, magic sparking to life, the little LV in his system intoning a song of intent, urging him to plunge his knife straight into that fastidiously red target of a soul-!

“ _ **Stand down.**_ ”

And he does, briefly shaking in place, not unlike a furious Chihuahua, before resuming taking his seat once more, eyelights burning inside his sockets like two lit matches, vision slowly getting clearer. Even as he calms down, he realizes it’s not much of an improvement, his stunt had startled the others into drawing their attacks out, and from how a nipping coldness was nipping at his neck, Nightmare was not pleased.

“It looks like you’re not apt just yet”, he hissed, “You’ll be going alone, Killer.”

Sockets widening in surprise, Cross intervenes, “B..but boss! I want to-“

The venomous glare the guardian of negativity is withering, killing the soldier’s voice instantaneously.

He doesn’t dare look up at Killer, the pit in his soul plummeting into shame the more his new boss glowers at him. It was…very irresponsible of his part to lose his cool like that, even if Killer was an insufferable bastard, even if he was irritated about being looked down at. 

“Yeah, ok, I can do that.”

“Hm, that’s all, you’re dismissed. I expect you all to be on your best behavior, I don’t need to explain what’ll happen otherwise.” With that, Nightmare turns on his heel and exits the dining room the same way he came in, leaving the rest to pick after themselves.

Cross, particularly, stands up and flees the scene he caused hastily, swinging the doors open and stomping off to a reasonable distance from the rest, before ducking beside a corner, out of sight.

There, he squeezes his sockets shut, rubbing at his forehead with the heel of his hand, red splotches of light dancing across his vision, a concentrated heat on his cheekbones worsening the incoming migraine. There’s a reason why he tried to keep his “soldier looking into the distance” aloof, stoic attitude- if he could convince himself that he was in control of his emotions, or his urges, maybe it’d become true. However, he as well as Chara knew there was something stronger than both of them driving their actions.

LOVE is a powerful weapon… in the right hands. On his, though, it was just like giving a child a firecracker and a lighter- one way or another, something was going to blow up. Without control of his newfound violent urges, Cross often finds himself in compromising situations caused by his inability to _think before acting_.

A violent throb inside his skull makes Cross hiss out a curse, verbally damning Killer’s very being, absolutely pinning the blame on the other.

Stars, what was his problem? If he has a personal issue with Cross, for whatever reason, he should keep it to himself or take it out on the training clearing outside. Nothing good came from testing or underestimating him- another reason Nightmare had probably picked him for.

Of course, there’s always the possibility of Killer only wanting to fuck with him, toy with the new guy before he learned the ropes.

“Fuckin’ asshole”, Cross mutters with a growl, rubbing his socket furiously.

“Aren’t ya just charming?”

Cross jumps a foot above the ground with a yell, blindly swatting at the air as he’s violently tipped from annoyance to defensive rage. It takes him two seconds to realize Killer was the one to startle him, hands in pockets and posture hunched- Not ashamedly, but nonchalant.

The soldier glares the best he can, tense posture clearly stating his unwillingness to listen to anything the other has to say. Still, Killer’s grin hitches higher at his fidgeting, and takes a step forward, making Cross, in turn, take one back.

“Relax teenage angst, I just wanna apologize”, he confesses, shrugging as a distrustful noise escapes Cross. “Sorry you’re such a lil sensitive kid, that is.”

“What the fuck do you want, Killer?” Cross snaps, patience running thin, “Got tired of riding Nightmare’s dick?”

“It’s really funny you mention that, you interested, Cross?”

He bristles embarrassingly fast, still roused from his earlier outburst, the fur of his vest prickling somehow, and the empty-eyed skeleton _giggles_.

“Holy shit, you’re easy, puffing up like a kitten at the smallest insult.” Killer sounds delighted in his findings, now confidently closing the distance between them, ignoring the way Cross’s face scrunches up in a snarl. “Makes a guy wonder how other ways yer easy.”

The threat is loud and clear, and Cross is ready to defend himself against anything Killer threw him, magic already agitated and stirred.

However, when Killer’s sockets narrow, and his trademark smirk drops unexpectedly, Cross tenses in a way his bones had never before, and the other’s next words are a replica of Nightmare’s earlier order.

“ _Stand down, Cross._ ”

A large part of his mind screams in reproach for his reaction, shoulders slacking, and fight response dulling out to a pleasant hum at the back of his mind. The more complaint, the more trained part of it mellows out at the strict tone, like a reset button being pushed and waiting for new information- unwilling to question it.

Next thing he knows, a rough hand pats his cheek condescendingly, and Cross is forced back to reality just to meet the empty voids of Killer’s sockets, his smile practically splitting across his face. 

He looks like he just discovered Cross’s darkest secret, and the soldier jerks his skull back to get away- only for his cheeks be squished together roughly as Killer held his face.

“Aren’t you a good little soldier, Cross?” he speaks with a sickeningly saccharine tone, contradicting the bloodthirsty expression he wears, “Bet you’d do anything in that state, all soft and plaint and willing.”

Cross’ head unhelpfully makes a turn, a complete backhanded slap of realization of what Killer was implying, and he releases an alarmed whimper as the other digs his phalanges into his face, making his teeth bite into the tender magic inside his mouth. His once limp hands rise to grasp at Killer’s wrist, but otherwise don’t attempt to free him.

His silence seems to spur Killer further, “But ya already knew that didn’t you? That’s why you’re here, ‘cuz you’re useless by yourself, you need someone to tell you what to do”, he sighs, dreamily, “And when you do, when you finally make a decision, ya fuck up.”

Cross tries to take Killer’s brief silence to defend himself, to deny the accusations, bite the hand holding him in place for the insults he’d been trying to fight off ever since the image of his Au vanishing inserted itself into his mind.

But Killer doesn’t let him, bringing Cross’s face closer to his own, just a hair away from touching, “And I think…you even enjoy it, don’t you? I see the way ya hide yer face all flustered after the boss is satisfied with your work. You like working, and you love serving and being acknowledged for it.”

It’s like he’s intoxicated, having just snapped out of his… _state_ … only to be immediately bombarded with the surgeon-precise wording from Killer. Or it’s more like a web, silky and soft, but ultimately a deadly trap that Cross, like an angry insect, fails to free himself from. In times like these, the soldier can see the Human part of Killer, able to rope anyone into whatever they wanted with sweet words and empty promises.

Destiny seems to want to see Cross fail over and over again for those pretty lies.

All of a sudden, Killer frees Cross’s face from his bruising grasp, and the soldier’s own desire to get away makes him stagger on his feet, hands flying to massage his sore cheeks as he watches how his captor returns his hands to his pockets passively.

As if nothing happened, Killer rounds Cross’s body easily. 

“O’ course, that’s just an assumption, Crossy. I’m looking forward to learning more about you.” 

…

Wait, what the fuck?

Had he let Killer pin him down like that- _let_ him _talk_ to him that way? 

As soon as Killer turns his back on Cross, he snaps, his red and white eyelights flashing dangerously, magic licking his sockets at the same time as he grasps the back of the other’s jacket, yanking him back hard enough to slam him against the hall wall. A loud “whack” thundered through the air as Killer’s skull smashed on the hard stone, bony brows furring in pain and feeding the little sadistic tendencies Cross usually attributes to Chara.

But not right now, this time it’s all his.

His hand wraps in a tight squeeze around Killer’s neck, lifting the other from his feet, listening to the choked up way Killer breathes, watching how the tables turn and he takes hold of Cross’s wrists in turn.

“Who _the fuck_ ya think you are?”, he spits, baring his fangs back in rage. Cross shakes Killer like that’ll give him the answers he wants- but all he gets is a kick on his hipbone that doesn’t hurt at all.

“You don’t know _shit_ about me, Killer. I’ve lived hundreds of years at the mercy of someone that was toying with my family and me.”

He slams Killer on the wall again, and the other’s sockets finally focus on his blazing lights, the circular shape of his soul flickering between its normal determined red, and pale wine color. The meaning is too new for Cross to decipher, and he has no intention to understand now.

“I watched how he turned my brother into a merciless killer- I watched my best friend bleed out on my arms”, he continues, voice wavering with an emotion he’d learned to store away for later. Killer stays silent, and Cross can’t tell if it’s because he’s in pain, actually listening, or speechless…maybe he was all three. “I’ve fought in a dozen wars, I’ve trained until my bones broke under the pressure.”

“I didn’t go through all of that just so a little nosy, needy _brat_ like you can go around underestimating me, thinking ya can bully me into obeying your stupid, little whim.”

Cross is about done talking right now, loosening his grip on the other’s neck slightly, but he re-adjusts it when Killer coughs out his response, smile wavering but still smug and void of fear as ever.

“N-now I get why Nightmare chose ya”, he admits, just before his voice turns _acidic_ , making Cross flinch, “Self-absorbed people like you are easy to manipulate s’long as ya keep letting them think they got a chance.”

It burns through the last bits of Cross’s patience, curling enticingly along his unchecked anger from before, compelling him into putting the insolent skeleton down to his feet, before proceeding to throw him to the ground, watching him catch himself on his hands and knees. Killer coughs loudly now, but no amount of raspy gasping or hoarse coughing can mask the hysterical laughing underneath.

The soldier sneers down to him, tempted to kick his ribcage while he’s down, but he knows Nightmare would be able to tell he roughed up Killer and decides what he’s done is enough.

“Stay the fuck away from me, Killer,” he growls, even as the other giggles raise in volume, “Or I swear I’ll kill you.”

Quickly, Cross walks back a few steps from Killer, making sure he won’t leap and attack him from behind but is promptly stopped by the derisive laugh from the downed skeleton.

“I hope that’s a threat ya plan to carry through, Crossy, ‘cause that was a challenge, what you’ve just said.”

…Cross keeps walking, this time back to his room until duty called him back.


End file.
